<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>let const</title>
	</head>
	<body>
		<script>
			let controller = {
				makeRequest: ()=> {
					window.setTimeout(()=> void console.log(this.a));
				},
				a: 1
			}

			controller.makeRequest(); //undefined
		</script>
	</body>
</html>
